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By Thomas A. Gelormino, Ulrich La Fosse

"Deep blasting was used to densify foundation soils for a large manufacturing facility inChicopee,Massachusetts. A 360,000 square foot building, whose construction began inthe summer of 1990, is founded on alluvial deposits up to 90 feet in depth. These deposits are comprised of saturated very loose to loose fine to medium grained sands with traces of silt and gravel. During the building foundation design it was found that to withstand earthquake forces without soil liquefaction, it would be necessary to improve portions of the alluvial deposits by densification. The zone in need of densification extended from approximate depths of 20 to 50 feet. Several conventional densification methods, including vibrocompaction and deep dynamic compaction, were evaluated along with deep blasting. Detonation of 1-3/4 inch diameter charges of 65 percent gelatin dynamite (Atlas Power Primer) installed inside 2-inch diameter PVC casings to a depth of up to 40 feet, was used to achieve the desired densification. This method was selected over others due to its lower cost and decreased construction time. Although used in New England once in1940 for a dam and once in 1960 for a transmission line tower to improve foundation soils, there is no precedent found in the literature for densification by blasting to improve liquefiable soils below a proposed building. Details of a test program and the production blasting, including vibration data are presented. Pre-and post-blasting data conclusely shows an increase in the density of the sand deposit after blasting."

Jan 1, 1991

By Joshua Hoffman, Braden Lusk, Perry Kyle

With the advent of any new technology comes the necessity of fully understanding the mechanics of that technology. The Shock Tunnel is one such technology that provides a cost effective means of simulating large-scale explosions while requiring a fraction of the explosive and space. Although the technique is known and practiced, the dynamics and mechanics of this technology has yet to be fully understood. A relationship between the energy potential of a given explosive and the energy realized at a set of distances was determined. This data was then compared to the energies realized from the same explosive when utilized in conjunction with a shock tunnel. A relationship between potential and realized energy outputs from explosive based shock tunnels exists and the understanding of this relationship would allow all for predictions to be made to forecast a specific amount of explosive required to produce a desired energy output. This energy output should then be relatable to peak pressures produced via the shock tunnel. Two shock tunnels are currently accessible for this study, the first under the direction of the University of Kentucky, and a second under the direction of the Missouri University of Science and Technology. The two shock tunnels differ in dimensions but share common construction materials. Energy realized from a shock tunnel is hypothesized to be a function of the shock tunnel’s dimensions. This study explores how different geometries affect the shock tunnel’s performance; this exploration is broken down into three phases. Phase 1: Open arena testing in which theoretical energies produced by the detonation of small (<1.0 kg) charges are compared to actual experimental values. Phase 2: Shock Tunnel testing in which realized energies are experimentally recorded for the UK shock tunnel. Phase 3: Analysis of the data to lay down the ground work for producing a pressure-forecasting tool given shock tunnel dimensions and explosive characteristics with the possible detection of avenues for optimization of shock tunnels.

Jan 1, 2009

By Lewis L. Oriard

Ground vibrations associated with blasting are generally in a higher frequency range and of shorter duration than those generated by earthquakes, and the intensity scales for earthquakes cannot be applied directly to blasting vibrations without modification. Further, the profession does not need an intensity scale merely to estimate vibration intensity. If the blasting in question was not monitored instrumentally, it is a simple matter to estimate the range of intensities based on published prediction formulae or data from various sources such as Oriard (1), Nicholls et al (2), Hendron and Oriard (3), Siskind et al (4), and others. However, the profession has a serious need, for purposes of evaluating damage claims, to understand the relationships between vibration intensities and the levels of observed effects. The criteria for threshold damage do not apply to typical cases which usually involve structural damage. If the damage in question would have required ground vibration with a particle velocity of, say, 20-120 ips, damage is not verified by showing that the vibration merely approached a suggested limit to avoid threshold damage. That is not the question. This paper provides some guidelines for comparing severity of damage to intensity of vibration which would be required to cause such damage, much as is done when determining earthquake intensities. In addition, this paper includes a discussion of strain amplitudes induced by environmental forces, the predominant causes of damage to structures. Also, certain popular myths regarding blasting damage are discussed in the paper. Due to space limitations, the paper will not include a discussion of airblast effects.

Jan 1, 1989

By Paulo Couciero

Since explosives are the source of all energy used for rock blast fragmentation and heave, multidimensional effects in the detonation driving zone become essential to better describe the detonation process. In order to use the explosive as an energy source-information for more realist blasting performance simulations, a simple and effective modelling strategy is desirable. Facing this challenge, an engineering approach to two-dimensional unconfined non-ideal detonation is proposed. Based on the elliptical construction of the shock locus, the model combines the axial cylindrical stick Q1D solution with some additional limiting conditions to determine the sonic edge of the charge. For a given set of rate law parameters and velocity of detonation, a complete axial solution is firstly computed through the Q1D model. From this solution, a vital relationship between the axial shock curvature with the shock shape parameters can be stablished. Once this relationship is found, the problem simply reduces in finding the shock shape parameters subject to the sonic edge condition. As a result of this calculation, the corresponding charge diameter can be found. Consequently, the proposed model can map the diametereffect curve by relating the unconfined velocity of detonation with its corresponding diameter. Finally, because of its low computation cost, the proposed engineering approach can be also used for characterizing the rate law parameters by fitting to data from unconfined detonation experiments

Jan 1, 2019

This paper describes the circuit simulations based on SPICE of the SDI Electronic Detonator System at the system level. SDI is launching the Electronic Detonator System with a robust serial protocol exhibiting great ease in field usability and deployment. Programmable delay time with increment of 1 ms up to 10s is possible. Bus length of up to 2 km containing 1600 detonators can be utilized. This system was analyzed using SPICE simulations and an Excel-based firing model spreadsheet. The effects of wire diameter, resistivity, detonator leakage characteristics, blasting array topology (lumped, linearly distributed or branched) were simulated using the firing model. Such spreadsheet is instrumental in determining the blasting topology of any given detonator number and bus wire diameter or resistivity. Initial simulation results were interactively coupled back into making the serial protocol more robust during typical mining conditions.

Jan 1, 2006

According to the Directive 93/15/EEC, given on 5th of April 1993, all the commercial explosives placed on the market and transfered in European Union and EFTA countries have to be certified and contain the CE-marking. Before the products can be awarded by the CE-marking they have to fulfil the Essential Safety Requirements (ESR) of Appendix 1 of the Directive. From the beginning of last year the commercial explosives could not have been be sold in Europian Union countries without the CE-marking. The legitimacy of the Directive 93/15/EEC encompasses High Explosives, Detonating Cords, Safety Fuses, Gun Propellants and Detonators. At the moment in Europe, there are seven Notified Bodies (NB) working in the field of commercial explosives. They are in Spain (LOM), Germany (BAM), France (INERES), England (HSL), Netherlands (TNO-PML), Sweden (SP) and in Finland (PvTT). The Swedish SP has qualifications only for the detonators and the Finnish PvTT for High explosives, Detonating cords, Safety Fuses and Gun Propellants, but not for the detonators. The role of the NB is to work as a third independent body between the client and the manufacturer testing, studying and certifying explosives by the commission of the manufacturer. The Notified Bodies are operating independently competing the clients, the explosives manufactures.

Jan 1, 2004

By Peter Duniam, Vivian Patz

History of the ExEx 1000 CAB system. l What we’ve learned using electronic timing. l Requirements for a second generation. EDD system. l The ExEx 2000 system - simple, versatile and cost effective

Jan 1, 1997

By A K. Raina, P B. Chourdhury

Flyrock is the unwanted throw of rock fragments to excessive distances in opencast blasting. The incidence is relative in nature incorporating the distance of objects of concern like structures within and outside the mine, equipment within the mine & near the blast and persons within and off the mine. Several attempts to predict and defi ne fl yrock made worldwide could not address the problem since the phenomenon is not a regular feature in blasting. This probabilistic nature of fl yrock allows for risk calculation. CIMFR, India developed a Factor of Safety based risk criterion (10, 14) for evaluation of throw/ fl yrock in opencast mines that incorporates all the above in terms of distance and allowable limit of throw – which in turn determines the risk. The criterion provides the blaster a tool for mathematical evaluation of fl yrock risk in terms of a Factor of Safety and threat ratio (defi ned for the 1st time), thereby enhancing confidence when blasting. The method is easy to use and has been applied to several mines in India and the results are signifi cant. This paper details the evolution of the concept and its application in three limestone mines of India and the results obtained. The application of the method for defi ning a fl exible danger zone is also discussed.

Jan 1, 2008

By Martin Chenoweth

The Metropolitan Water District of Southern California (MWD) is undertaking one of the nations largest water management projects. The Eastside Reservoir Project is being built to insure a supply of water to Southern California in the event of earthquake damage to the aqueducts supplying the region. An 800,000-acre-ft lake will result from the three dams, closing off the valley between two parallel ridges. The single largest contract of the project, the West Dam, was awarded to the joint venture of Atkinson Construction Co., Washington Construction Co. (Morrison Knudsen Co.), and HB Zachry Co. Over 50 million bank cubic yards of rock must be drilled and shot on this contract alone. AWZ relies on the TechBASE database management system for documenting drilling and blasting. The database format of TechBASE allows all production parameters to be linked to the location of the activity. This allows parameters such as drill penetration or boulder production to be analyzed for geologic trends that can either be exploited or dealt with. Shot locations are stored as 3D polygons in a polygon table. Production and cost data are stored in flat tables. Shot names are unique and link the polygon table to the flat table. This allows typical database queries to be made by date, location, cost or any production parameter. The output from these queries can be presented in table, graph and as map formats. The map output is particularly helpful in quantifying geologic conditions and blast performance. The ability to transform the data into information has been very helpful. The ability to present this information graphically has been invaluable.

Jan 1, 2000

By Blenda Lopes, Rodolfo Matias, Vagner Paixão, Vinicius Leão VALE, Edivarde Sousa

Seismography is an extremely important subject in the context of rock blasting, especially in the current scenario, which involves the need for increased controls due to the growth of urban areas near open-pit mining operations. Worldwide, communities are becoming increasingly aware of the environmental and social impacts associated with mining activities. Therefore, maintaining good relationships with these stakeholders is essential to preserve the social license to operate and to comply with current legislation. This situation is exemplified in an open-pit iron mine near the capital of Minas Gerais, Brazil, where the community is located less than 40 meters from the pit boundaries. Blasting activities within the mining area occur at distances less than 500 meters from the nearest community, making continuous seismograph monitoring necessary to ensure that operational conditions are maintained without compromising exploitation efficiency. The threshold for peak particle velocity, according to Brazilian Standard 9653:2018 by ABNT, is 15 mm/s at frequencies around 4 Hz. However, even though the peak particle velocity commonly registered was inferior to 3 mm/s, there were still complaints from nearby residents regarding human discomfort. To further reduce vibration levels, a study was conducted to implement a new blast design, considering factors such as reducing bench height, altering the hole delays, maintaining the maximum charge per delay, and adjusting the drilling pattern without negatively affecting rock fragmentation quality. Following the implementation of the revised blasting parameters, seismographic measurements in the region decreased to below 0.6 mm/s. This significant reduction in ground vibrations contributed to minimizing community disturbances and fostering a more positive relationship between the company and its surrounding residents.

Jan 26, 2026

By S S. Kahlon

India is a large and growth market for explosives and accessories, which has dramatically changed from complete import dependence to self sufficiency, and now has an exportable surplus. The largest single user is coal mining which is continuing to show a healthy growth with opencast mining becoming increasingly dominant. The explosives industry has kept pace with mining and today all the well renowned explosives technologies of the world are available in the country. While slurry explosives are popular in large diameter, NG based explosives continue to be preferrred in small diameter usage. Emulsion explosives have had a good market response. ANFO usage is limited due to local reasons. As the mine size is increasing, the demand for bulk-on-site explosives is growing. Prices of explosives and accessories are cheap compared to international levels. The user industry is mainly Government owned mines whose profitability is not satisfactory. Explosives industry is over licensed in terms of manufacturing capacity, which is likely to put pressure on the viability of some of the explosives manufacturing units. Scope exists for optimization of blasting parameters through the use of computerized blasting models. The explosives industry is faced with new challenges and opportunities.

Jan 1, 1987

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Savas Gorgun

The principal disturbances created by blasting in open pit mines are vibrations, air blast and fly rock. All of them, under some circumstances, caused damage to structures nearby and apart from this can be the source of permanent conflict with the inhabitations who live close to the operation. Therefore, prediction of ground vibration components is of great importance for the minimisation of the environmental complaints. This paper presents the result of ground vibration measurements induced by bench blasting realised at Can Open Pit Coal Mine located close to the residential area of Can town. Within the scope of this study, in order to predict peak particle velocity and determine the slope of the attenuation curve for this site, ground vibration components were measured for blast events during bench blast optimisation studies over a long period. During the study, while the parameters of scaled distance were recorded carefully, the ground vibration components were measured by means of two different types vibration monitors (White Mini-Seis and Instantel Minimate Plus Model) for 54 blast events. At the end of evaluation an empirical relationship with reasonable correlation was established between peak particle velocity and scaled distance for this site.

Jan 1, 2001

By Lewis L. Oriard

The purpose of this paper is to provide an overview of close-in blasting effects on various types of structures and building materials, as encountered in this writer's professional practice. Structures range from old, deteriorated historical monuments to new, heavily reinforced buildings. Materials range from clay adobe to concrete and steel. Site locations range from tropical to arctic. Blasting ranges from sculpture blasting inside buildings to "coyote" blasting and large surface blasting operations. Space limitations permit a brief discussion of only 25-30 specific cases, but they have been selected to be typical of conditions found on hundreds of similar cases. The writer was asked to present a discussion of representative cases where relatively high vibration intensities were experienced. Virtually all of these cases were free of damage, but the few damage cases provide valuable insight to the mechanisms involved. Observations of such damage and non-damage cases have served as the basis of this writer's criteria for various structures and materials, as well as the technology to conduct blasting operations within those criteria. A sampling of these experiences is gladly shared with the reader.

Jan 1, 1991

By Bengt Ljung

Manual charging of long upward drilled holes in mines is a heavy and risky job today. Mechanization of this work has been requested for some time by miners, their supervisors, industrial safety organizations and the trade unions, all of whom are interested in improving the working environment. This paper presents newly-developed charging systems intended primarily for charging in connection with sublevel caving and sloping. These systems have been field-tested during 1977 in the LKAB mines in northern Sweden. The results of these field tests and the results of laboratory work conducted to help eliminate the risks involved in charging explosives are also discussed. The equipment being tested (see fig. 1 and 2) consists of a charging vehicle with articulated steering, the PT-60, which has been equipped with a hose feed system mounted on the hydraulic extension boom. From a sheltered position, the operator brings the detonator and primer to the hole opening, after which the hose is pushed in mechanically to the end of the hole. Measuring equipment indicates when and if the end of the blasthole is reached. The operator then withdraws the hose mechanically as charging takes place.

Jan 1, 1978

By K. G. Holley

Blasting is usually required to produce easily-excavated broken rock, while leaving surrounding rock masses as undamaged and stable as possible. In mining applications, it is common to utilise production blasting in the centre of an open pit, and specially developed limits blast designs when blasting adjacent to the excavation perimeter. In open pit blasting, limits blast designs generally include pre-splitting, trim blasts, or buffer blasts, all of which are designed to limit, or eliminate, damage beyond the designed pit wall. This paper reports on the findings of a study of the profile of damage in rock masses surrounding blasts, determined by a combination of vibration monitoring, displacement monitoring using extensometers, and video inspection of open holes drilled at various distances behind blasts. The results obtained suggest that the profile of damage may extend for the full depth of the bench, for distances of up to 12 to 15 metres behind blasts. This suggests that entire berms may be affected by blasting, displaying loss of friction and cohesion along joint and fracture planes. The study has considered production blasts and trim blasts with small diameter blastholes and pre-splits.

Jan 1, 2004

By Edward Fitch

The DOE is evaluating Yucca Mountain, Nevada as a potential site for disposal of high level nuclear waste. Yucca Mountain is located approximately 160 km northwest of Las Vegas on the western edge of the Nevada Test Site and the Nellis Air Force Range. An exploratory tunnel has been constructed through Yucca Mountain for site characterization. A controlled drilling and blasting technique, smooth wall blasting, was used to excavate the TBM starter tunnel and alcoves off the main tunnel to provide areas for scientific investigation. Fundamental to the blasting program has been the use of two blast design equations used in concert to minimize blast damage to the surrounding rock mass. The first of these equations was developed by Roger Holmberg and estimates near-field peak particle velocity that is the basis for minimizing blast damage to the host rock. The second of these equations was developed by B. H. Sanden and provides bore hole pressure estimation which allows controls to minimize crushing of the rock mass along the perimeter yet allowing enough force to create tensile failure between perimeter bore holes. This is key to the smooth wall blasting technique. To date, essentially the same controlled drilling and blasting program has been in place for all excavation requiring controlled drilling and blasting at the ESF. The controlled drilling and blasting program uses an iterative process to achieve continuous improvement in the blast rounds. This involves interaction between Architect and Engineer (A/E), Constructor, and Testing Coordination O&e (TCO) to ensure each blast round successfully meets the expectations of affected participants. The A/E requested that the TCO provide validation of the near-field peak particle velocity estimation under the Construction Monitoring Program. Data gathered under this program were reduced by statistical analysis and used to verify blast design parameters and provide a site specific blast damage relationship.

Jan 1, 2000

By Max Pena Woolcott, Winfried Rosenstock, Maria Chappuis, Walther Hennig

"In a Peruvian-German Technical Cooperation project for the Mining Sector the ""Milpo-cut"" along with the electric initiation system has been successfully implemented in a Peruvian metal-ore mine.Specific savings in drill work and explosives consumption up to 50 % have been achieved in headings and slopes. The positive results have motivated further Peruvian mining companies to introduce the new technique."

Jan 1, 1994

By E. Contestabile, B. von Rosen, P. Lightfoot

As part of an accident investigation ANFO was subjected to various abusive tests. A tractor-trailer carrying 18,000 kg of blasting explosives, caught fire, burned for approximately 30 minutes, and then detonated. A series of tests was designed to observe the behaviour of ANFO when subjected to different thermal stimulus tests and more specifically, the Height-to-Detonation Test. Three diameters of steel pipes were used in the Height-to-Detonation Tests thereby simulating cylindrical columns within a pile of ANFO. The ANFO samples were then subjected to various thermal stimuli to initiate a reaction. Through the use of some instrumentation, the response of large ANFO samples was recorded and its behaviour, including the occurrence of phase changes will be analysed.

Jan 1, 2001

By John Floyd, Larry Wardrip

A series of tests were conducted to evaluate the performance of a high density, high velocity cartridged explosive. The tests included two production blasts in a limestone quarry and two production blasts in a granite quarry. To quantify blast and product performance, each blast was monitored with the following equipment: l Two (16mm (Lo Cam) high speed cameras (500 images per second) l Velocity of detonation recorder (I million samples per second) l Four face motion accelerometers (1 million samples per second) l Digital seismograph The fragmentation distribution produced by each blast was quantified with digital image analysis The benefits of the use of high velocity, high density toe loading was quantified in terms of: l Vibration reduction l Fragmentation improvement l Excavator performance In addition to the field tests, a comprehensive evaluation was performed to determine the cost/benefit relationship of the use of the toe load. This paper will include the findings of the study along with guidelines for use in other quarry operations.

Jan 1, 2002

By Paul Worsey, Richard P. Ayres, Mark F. C. Schmidt

A new alternative technique designed to reduce rock scatter and flyrock during boulder blasting is being developed at UMR. The method uses small explosive charges and is designed for shooting in close proximity, while utilizing common blasting products found on the operators’ site. This ongoing work is being conducted internally as graduate and undergraduate level research. A paper describing the general technique was published in last year’s proceedings. This particular portion of the work was performed as an undergraduate research project as part of the requirements for the explosives emphasis degree option at UMR. Previous model work was performed using cubes of concrete. However, in real life boulders are often flat and irregular rather than perfect cubes. The purpose of this work was to determine how to deal with flatter boulders. The work comprised using different geometry blocks (simulated boulders) of the same volume (1 cubic ft.). Square concrete boulders using an 8.5bag concrete mix were cast using different width to height ratios (varying from 1: 1 to 3.7:1). Single 5/8 inch holes were drilled to 2/3 the depth of the blocks, charges placed approximately l/2 way in to the holes and the holes filled with water. The explosive charges comprised ICI Masterdets containing a OSg High Explosive base charge and incremental added weights of C4 explosive. In the experiments, the block height was progressively reduced and to compensate the charge weight was increased until acceptable fragmentation was achieved. It was found that a significant increase in charge wt is required to achieve the same fragmentation as the width to height ratio increases (the boulder becomes flatter). Furthermore, the increase in charge weight required is proportional to the width to height ratio. Basically, you have to use a higher powder factor for flatter boulders.

Jan 1, 2000